Network service providers are increasingly providing network services such as security, tunneling, virtual private networks, filtering, load-balancing, VoIP/Multimedia processing and various types of application proxies (HTTP, XML, WAP, etc.) to packet flows from customer devices. Service providers also provide content-specific services designed to improve the quality of a user's experience, for example, video streaming and caching. To provide these new services, service providers have often turned to specialized, dedicated physical or virtual appliances. In some cases, routers or other network device have been modified to include additional hardware or software that applies various services to the incoming packets. For example, line cards installed in a service plane of a router may be configured to perform particular services, such as the services described above. In other example, service providers have deployed sophisticated service complex of specialized physical and/or virtual appliances to apply services to customer packet flows.
In some example implementations, physical and/or virtual appliances of the service complex are configured in the form of service chains that provide network services to customer packet flows. In a typical network deployment, instantiation of service nodes executing virtual machines (VMs) implementing virtual network functions (VNFs) to create a service chain providing the requisite network function may take anywhere from ten minutes to multiple hours, depending upon complexity and the particular network environment. This onerous start-up time negatively impacts the experience of the end user. Each time a new service chain is created to handle traffic from a subscriber device, the end user is often forced to wait a long period for the new service chain to initialize.